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Abstract:

According to an embodiment, a semiconductor light emitting device
includes a stacked body including a first semiconductor layer of a first
conductivity type, a second semiconductor layer of a second conductivity
type different from the first conductivity type, and a light emitting
layer provided between the first semiconductor layer and the second
semiconductor layer. A transparent electrode is provided on a first major
surface of the stacked body on a side of the first semiconductor layer,
the transparent electrode having a thin part, a first thick part thicker
than the thin part, and a plurality of second thick parts thicker than
the thin part and extending along the first major surface from the first
thick part. A first electrode is provided on the first thick part; and a
second electrode is electrically connected to the second semiconductor
layer.

Claims:

1. A semiconductor light emitting device, comprising: a stacked body
including a first semiconductor layer of a first conductivity type, a
second semiconductor layer of a second conductivity type different from
the first conductivity type, and a light emitting layer provided between
the first semiconductor layer and the second semiconductor layer; a
transparent electrode provided on a first major surface of the stacked
body on a side of the first semiconductor layer, the transparent
electrode having a thin part, a first thick part thicker than the thin
part, and a plurality of second thick parts thicker than the thin part
and extending along the first major surface from the first thick part ; a
first electrode provided on the first thick part; and a second electrode
electrically connected to the second semiconductor layer.

2. The device according to claim 1, wherein a maximum width of the second
thick part orthogonal to a direction of the extension is smaller than a
minimum width of the first thick part in a plane parallel to the first
major surface.

3. The device according to claim 1, wherein the stacked body has a
rectangular shape with a long side and a short side, in a planar view
parallel to the first major surface, a longitudinal direction of the
first thick part corresponds to a direction along the short-side of the
rectangular shape, and a longitudinal direction of the second thick part
corresponds to a direction along the long-side of the rectangular shape.

4. The device according to claim 1, wherein the stacked body has a shape
of a rectangular shape with a long side and a short side, in a planar
view parallel to the first major surface, the first thick part is
provided in a region including a center of the rectangular shape, and the
second thick part extends from the first thick part in a long-side
direction and in a short-side direction of the rectangular shape.

5. The device according to claim 1, wherein the stacked body has a
rectangular shape with a long side and a short side, in a planar view
parallel to the first major surface, the first thick part has a region
including a center of the rectangular shape and has a portion extending
along the long-side from the region including the center of the
rectangular shape, and the second thick part has a portion extending
along the short side from the region of the first thick part including
the center of the rectangular shape, and has a portion extending along
the short-side from the portion of the first thick part extending along
the long-side of the rectangular shape.

6. The device according to claim 1, wherein the stacked body is provided
on a substrate in sequence of the second semiconductor layer, the light
emitting layer and the first semiconductor layer.

7. The device according to claim 6, wherein the substrate is one of a
sapphire substrate, a silicon substrate, an SIC substrate, and a GaN
substrate.

8. The device according to claim 6, wherein the first semiconductor layer
includes an carrier block layer provided on a side of the light emitting
layer for preventing electrons from overflowing from the light emitting
layer, and a contact layer of a first conductivity type provided on a
side of the transparent electrode.

9. The device according to claim 1, wherein the second electrode is
provided on a second major surface of the stacked body on a side of the
second semiconductor layer and reflects light emitted from the light
emitting layer.

10. The device according to claim 9, wherein the second electrode
includes a multilayer film containing at least one of silver (Ag) and
gold (Au).

11. The device according to claim 9, further comprising a current
blocking layer provided between the second electrode and the second
semiconductor layer to block a current flowing between the transparent
electrode and the second electrode, wherein the second thick part has a
portion not overlapping the current blocking layer, in a planar view
parallel to the first major surface.

12. The device according to claim 11, wherein the current blocking layer
includes a silicon oxide film.

13. The device according to claim 11, wherein the current blocking layer
is provided under the first electrode, in a planar view parallel to the
first major surface.

14. The device according to claim 9, further comprising a support
substrate on a side of the second semiconductor layer, wherein the second
semiconductor layer is provided between the support substrate and the
light emitting layer.

15. The device according to claim 1, wherein a thickness of the first
thick part and a thickness of the second thick part are the same.

16. The device according to claim 1, wherein a thickness of the thin part
is not more than 1/2 of a thickness of the second thick part.

17. The device according to claim 1, wherein the transparent electrode is
provided inside an outer edge of the first major surface.

18. The device according to claim 1, wherein the transparent electrode
contains at least one of ITO, ZnO, and Sn2O.

19. The device according to claim 1, wherein the light emitting layer
includes a multiple quantum well in which well layers and barrier layers
are alternately stacked.

20. The device according to claim 1, wherein the first electrode includes
a multilayer film containing nickel (Ni) and gold (Au)

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priority
from Japanese Patent Application No. 2011-92486, filed on Apr. 18, 2011;
the entire contents of which are incorporated herein by reference.

[0003] In recent years, semiconductor light emitting devices have been
widely used in fields of lighting equipment, displays, and the like, and
have been required to be improved in light output. For example, a light
emitting diode (LED), as one of the semiconductor light emitting devices,
has a transparent electrode for current spread and light extraction on a
light emitting face, thereby achieving improvement in light output.

[0004] Meanwhile, the semiconductor light emitting devices are greatly
expected to reduce power consumption. Accordingly, it is desired that the
semiconductor light emitting devices are not only improved in light
output but also enhanced in light emission efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIGS. 1A and 1B are schematic views illustrating a semiconductor
light emitting device according to a first embodiment;

[0006]FIG. 2 is a schematic view illustrating a characteristic of the
semiconductor light emitting device according to the first embodiment;

[0007]FIG. 3 is a schematic view illustrating a detailed cross-sectional
structure of the semiconductor light emitting device according to the
first embodiment;

[0008] FIGS. 4A and 4B are schematic views of a semiconductor light
emitting device according to a second embodiment.

[0009] FIGS. 5A to 7B are cross-sectional views illustrating manufacturing
processes of the semiconductor light emitting device according to the
second embodiment;

[0010] FIGS. 8A and 8B are schematic plan views illustrating a
semiconductor light emitting device according to a variation of the
second embodiment.

DETAILED DESCRIPTION

[0011] In general, according to an embodiment, a semiconductor light
emitting device includes a stacked body including a first semiconductor
layer of a first conductivity type, a second semiconductor layer of a
second conductivity type different from the first conductivity type, and
a light emitting layer provided between the first semiconductor layer and
the second semiconductor layer. A transparent electrode is provided on a
first major surface of the stacked body on a side of the first
semiconductor layer, the transparent electrode having a thin part, a
first thick part thicker than the thin part, and a plurality of second
thick parts thicker than the thin part and extending along the first
major surface from the first thick part. A first electrode is provided on
the first thick part; and a second electrode is electrically connected to
the second semiconductor layer.

[0012] Embodiments will now be described with reference to the drawings.
Throughout the drawings, identical components are marked with identical
reference numerals, and detailed descriptions thereof are omitted as
appropriate in the specification of the application.

First Embodiment

[0013] FIGS. 1A and 1B are schematic views of a semiconductor light
emitting device 100 according to a first embodiment. The semiconductor
light emitting device 100 is a blue LED made of a nitride semiconductor,
for example, and FIG. 1A is a schematic plan view of its chip face. FIG.
1B is a cross sectional view showing a cross section taken along a line
Ib-Ib in FIG. 1A.

[0014] As shown in FIGS. 1A and 1B, the semiconductor light emitting
device 100 includes a stacked body 10 provided on a sapphire substrate 3,
for example. In addition, as shown in FIG. 1A, the stacked body 10 is
provided in a rectangular shape with a long side and a short side, in a
planar view parallel to a light emitting face 10a as a first major
surface of the stacked body 10.

[0015] The light emitting face 10a is provided with a transparent
electrode 13. The transparent electrode 13 has a thin part 13c, a first
thick part 13a thicker than the thin part 13c, and a second stripe-shaped
thick part 13b that is thicker than the thin part 13c and extends from
the first thick part 13a along the light emitting face 10a.

[0016] In the embodiment, as shown in FIGS. 1A and 1B, a longitudinal
direction of the first thick part 13a corresponds to a short-side
direction of the rectangular light emitting face 10a, and a longitudinal
direction of the second thick part 13b corresponds to the long-side
direction of the light emitting face 10a. In addition, a thickness of the
second thick part 13b and a thickness of the first thick part 13a are the
same.

[0017] The same thickness here is not limited to an identical thickness in
a strict sense. For example, there may a difference in thickness between
the thick part 13a and the thick part 13b, resulting from a thickness
distribution of the transparent electrode 13 except for the thin part
13c.

[0018] As shown in FIG. 1A, the semiconductor light emitting device 100
includes a p electrode 15 as a first electrode and an n electrode 17 as a
second electrode, and emits light from the light emitting face 10a when a
drive current flows from the p electrode 15 to the n electrode 17. The p
electrode 15 is provided on the thick part 13a and is electrically
connected to the transparent electrode 13. The n electrode 17 is provided
on a surface of an n-type clad layer 5 exposed in the chip face, and is
electrically connected to the n-type clad layer 5.

[0019] Meanwhile, as shown in FIG. 1B, the stacked body 10 has a p-type
clad layer 7 as a first semiconductor layer, the n-type clad layer 5 as a
second semiconductor layer, and a light emitting layer 9 provided between
the p-type clad layer 7 and the n-type clad layer 5. Light emitted from
the light emitting layer 9 is mainly extracted from the light emitting
face 10a as a surface of the p-type clad layer 7. In addition, as shown
in FIG. 1B, the light emitting face 10a constitutes the surface of the
p-type clad layer 7 and also the first major surface of the stacked body
10.

[0020] The transparent electrode 13 made of indium tin oxide (ITO), for
example, is provided on the surface of the light emitting face 10a. As
described above, the transparent electrode 13 is provided with the thick
part 13b, and the thin part 13c that is thinner than the thick part 13b
in a direction perpendicular to the light emitting face 10a.

[0021] ITO is a conductive film that lets visible light pass through, and
has a sheet resistance higher than sheet resistances of metal films, such
as gold (Au), aluminum (Al), and the like. Therefore, as shown in the
embodiment, formation of the thick parts 13a and 13b and the thin part
13c on the transparent electrode 13 makes differences in electric
resistance significant for the driving current flow. Accordingly, an
electric current to be injected into the light emitting layer 9 through
the thick part 13b, can be made larger than an electric current injected
into the light emitting layer 9 through the thin part 13c.

[0022]FIG. 2 is a graph schematically showing characteristics of the
semiconductor light emitting device 100, where a horizontal axis shows a
drive current I and a vertical axis shows a light output L.

[0023] In FIG. 2, graph A shows I-L characteristics of the semiconductor
light emitting device 100, and graph B shows I-L characteristics of a
semiconductor light emitting device according to a comparative example
(not shown). The semiconductor light emitting device according to the
comparative example is different from the semiconductor light emitting
device 100, in that the thick parts 13a and 13b are not provided and the
transparent electrode 13 has a uniform thickness.

[0024] If the transparent electrode 13 of a uniform thickness is formed on
an entire face of the light emitting face 10a, a drive current spreads
over the entire face of the light emitting face 10a and is injected into
the light emitting layer 9. Accordingly, the entire light emitting layer
9 emits light uniformly, and exhibits the I-L characteristics of the
graph B, for example.

[0025] The light output L shown in the graph B increases monotonously with
increase in the drive current ID. However, the increase rate of the
light output L to the drive current ID, is small with low light
emission efficiency, in a low injection region IL with the smaller
drive current ID. When the drive current flows beyond the low
injection region IL, the increase rate of the light output L becomes
higher with improvement in light emission efficiency.

[0026] Further, as the drive current ID is increased to reach a high
injection region IH, the light output L shows a saturation tendency.
For example, considering life time and controllability of the
semiconductor light emitting device, it may be used in a practical range
where the drive current ID is smaller than in the high injection
region IH.

[0027] In contrast to this, in the semiconductor light emitting device
100, the increase rate of light output is improved from the low injection
region IL, and higher output is provided in the practical range, as
compared with the comparative example. This advantage will be described
as below.

[0028] Carriers (electrons and holes) injected by the drive current
ID into the light emitting layer 9 include ones that recombine with
light emission and ones that recombine through a non-light emission
process. For example, a Shockley-Read-Hall (SRH) process is known as
non-light emission processes, where the carriers recombine through a deep
level in a bandgap. If a small number of carriers are injected into the
light emitting layer 9, such non-light emitting recombination occurs at a
high rate. Since the number of deep levels--contributing to the non-light
emitting recombination is limited, the rate of light emitting
recombination becomes higher with a larger number of carriers. Thereby it
is possible to improve the light emission efficiency. Accordingly, the
I-L characteristics as shown in the graph B are exhibited.

[0029] Meanwhile, in the semiconductor light emitting device 100, a larger
amount of the drive current ID flows through the thick parts 13a and
13b of the transparent electrode 13, and therefore the density of
carriers in the light emitting layer 9 becomes higher at portions under
the thick parts 13a and 13b than at a portion under the thin part 13c. As
a result, the portions of the light emitting face 10a provided with the
thick parts 13a and 13b actively contribute to light emission.

[0030] That is, in the semiconductor light emitting device 100, a light
emitting region is substantively narrowed to raise the density of
carriers in the low injection region IL. This decreases the rate of
non-light emitting recombination, and improves light emission efficiency
as compared with the comparative example.

[0031] Meanwhile, in the high injection region IH with the larger
drive current ID, the density of carriers in the light emitting
layer 9 under the thick parts 13a and 13b of the semiconductor light
emitting device 100 becomes higher than the density of carriers in the
comparative example. Therefore, current loss increases due to an overflow
of electrons flowing from the light emitting layer 9 to the p-type clad
layer 7, an Auger effect, or the like, thereby resulting in a significant
saturation tendency of the light output L. As a result, the light output
L of the semiconductor light emitting device 100 in the high injection
region IH becomes lower than the comparative example, but does not
cause any problem in practical use as far as the light output L exceeds
the comparative example, in the practical range of the drive current
ID.

[0032] For example, if the transparent electrode 13 is removed from the
thin part 13c, it is possible to increase current flowing through the
thick parts 13a and 13b and further improve light emission efficiency in
the low injection region IL. In this case, however, the density of
electrons and holes in the light emitting layer 9 under the thick parts
13a and 13b excessively increases, and thereby an overflow of electrons
is prone to occur, for example. Accordingly, the light output L exhibits
a saturation tendency from the region with the lower drive current
ID, which may make the light output lower than in the comparative
example, in the practical range. Therefore, the semiconductor light
emitting device 100 has the thin part 13c retained to suppress excessive
current concentration in the thick parts 13a and 13b.

[0033] Further, current flows into the light emitting layer 9 through the
thin part 13c, thereby suppressing light absorption in the light emitting
layer 9. That is, the light emitting layer 9 with the lower carrier
density functions as a light emission absorber. Therefore, retaining the
thin part 13c for injection of carriers into the light emitting layer 9
thereunder also makes it possible to suppress light absorption and
improve light emission efficiency.

[0034] In addition, to avoid excessive current concentration in the thick
parts 13a and 13b, the stripe-shaped thick part 13b desirably extends to
the entire face of the light emitting face 10a, or to a wide region of
the light emitting face 10a. For example, in the example shown in FIG.
1A, the square thick part 13a extending in a direction along the short
side of the light emitting face 10a and a plurality of thick parts 13b
extending from the thick part 13a in a direction along the long side of
the light emitting face 10a, are provided to allow a wide central region
of the light emitting face 10a to emit light evenly.

[0035] Further, in a plane parallel to the light emitting face 10a, for
example, a maximum width W2 orthogonal to an extending direction of
the thick part 13b is made smaller than a minimum width W1 of the
thick part 13a. This allows the drive current ID injected from the p
electrode 15 to spread uniformly over the entire thick part 13a with low
sheet resistance and flow evenly into the plurality of the thick parts
13b. As a result, it is possible to avoid local current concentration and
improve light emission efficiency and light output.

[0036] In addition, as shown in FIGS. 1A and 1B, the transparent electrode
13 is provided inside an outer edge of the light emitting face 10a. That
is, the transparent electrode 13 is not provided at a portion along the
outer edge of the light emitting face 10a. For example, surface defects
exist in high density on side faces of the stacked body 10. Accordingly,
if a drive current flows into the outer edge of the stacked body 10,
non-light emitting recombination increasingly occurs with lower light
emission efficiency. Therefore, when the transparent electrode 13 is not
provided at a portion along the outer edge of the light emitting face
10a, it is possible to suppress a drive current flowing into the outer
edge of the stacked body 10 and avoid reduction in light emission
efficiency.

[0037]FIG. 3 is a schematic view of a detailed cross-sectional structure
of the semiconductor light emitting device 100. As described above, the
semiconductor light emitting device 100 is a blue LED made of a nitride
semiconductor formed on the sapphire substrate 3.

[0038] The semiconductor light emitting device 100 includes the n-type
clad layer 5, the light emitting layer 9, and the p-type clad layer 7,
which are provided on the sapphire substrate 3. For example, the n-type
clad layer 5 is an n-type GaN layer with a thickness of 2.0 μm. The
light emitting layer 9 has a multiple quantum well (MQW) structure in
which In0.2Ga0.8N layers and In0.05Ga0.95N layers are
alternately stacked. The MQW structure includes eight quantum wells, for
example, which are each formed by 2.5 nm-thick well layers
(In0.2Ga0.8N layers) and 10 nm-thick barrier layers
(In0.05Ga0.95N layers) sandwiching the well layers.

[0039] The p-type clad layer 7 includes a carrier block layer 7a formed by
a 10 nm-thick p-type Al0.15Ga0.85N layer for preventing
electrons from overflowing from the light emitting layer 9, and a 40
nm-thick p-type GaN layer 7b, and a 5 nm-thick contact layer 7c, which
are stacked from the light emitting layer 9 side, for example.

[0040] The transparent electrode 13 is provided on the p-type clad layer
7. The transparent electrode 13 may use an ITO film, a zinc oxide (ZnO)
film, or a tin oxide (Sn2O) film, for example. The transparent
electrode 13 is provided with a thickness of 400 nm, for example. In
addition, a surface of the transparent electrode 13 is etched in a
predetermined pattern, thereby to form the thick parts 13a and 13b of a
thickness of 400 nm, and the thin part 13c of a thickness of 200 nm.
Alternatively, the thickness of the thin part may be not more than 200
nm.

[0041] The contact layer 7c as an uppermost layer of the p-type clad layer
7 is a p-type GaN layer in which Mg as a p-type impurity is doped with
high concentration, for example, and is provided to lower a contact
resistance between the transparent electrode 13 and the p-type clad layer
7.

[0042] The p electrode 15 is provided on the thick part 13a of the
transparent electrode 13. In addition, the p-type clad layer 7 and the
light emitting layer 9 are selectively etched to define the light
emitting face 10a as the first major surface of the stacked body 10.
Further, the n electrode 17 is provided on the surface of the n-type clad
layer 5 exposed by etching the p-type clad layer 7 and the light emitting
layer 9.

[0043] The foregoing configuration of the semiconductor light emitting
device 100 is merely an example, and may be modified in various manners.
For example, instead of the sapphire substrate 3, a silicon substrate, an
SIC substrate, a GaN substrate, or the like, may be used. In addition, a
superlattice buffer layer may be inserted into between the n-type clad
layer 5 and the light emitting layer 9, for example.

Second Embodiment

[0044] FIGS. 4A and 4B are schematic views of a semiconductor light
emitting device 200 according to a second embodiment. FIG. 4A is a plan
view of a chip face of the semiconductor light emitting device 200. FIG.
4B is a schematic view of a cross section taken along a line IVb-IVb in
FIG. 4A.

[0045] As shown in FIG. 4A, in the semiconductor light emitting device
200, a transparent electrode 13 is provided on a light emitting face 20a
as a first major surface of a stacked body 20. The transparent electrode
13 has a first thick part 13a, and a second thick part 13b extending in a
stripe shape from the first thick part 13a. An n electrode 29 as a first
electrode is provided on the first thick part 13a.

[0046] For example, the thick part 13a is provided in the shape of a
rectangle extending along a short side of the light emitting face 20a,
and the thick part 13b extends in a stripe shape along a long side of the
light emitting face 20a. In addition, a plurality of thick parts 13b
extend to near an outer edge of the light emitting face 20a to allow the
light emitting face 20a to emit light evenly. Further, the transparent
electrode 13 is provided inside the outer edge of the light emitting face
20a.

[0047] As shown in FIG. 4B, the stacked body 20 in the embodiment is
provided on a support substrate 25 via a p electrode 21 as a second
electrode. The stacked body 20 has an n-type clad layer 5 as a first
semiconductor layer, a p-type clad layer 7 as a second semiconductor
layer, and a light emitting layer 9 provided between the n-type clad
layer 5 and the p-type clad layer 7.

[0048] The transparent electrode 13 is provided on the light emitting face
20a as the first major surface of the stacked body 20 and a surface of
the n-type clad layer 5. The transparent electrode 13 has the thick part
13b relatively thicker in a direction perpendicular to the light emitting
face 20a, and a thin part 13c thinner than the thick part 13b.

[0049] The semiconductor light emitting device 200 is configured in such a
manner that the p electrode 21 is provided on a second major surface 20b
of the stacked body 20 and a drive current flows from the p electrode 21
to the transparent electrode 13 provided on the first major surface 20a,
thereby emitting light from the light emitting layer 9.

[0050] The p electrode 21 is provided so as to reflect the light emitted
from the light emitting layer 9 in a direction toward the light emitting
face 20a. For example, the p electrode 21 can contain silver (Ag) or gold
(Au) at a portion near the p-type clad layer 7, thereby reflecting blue
light emitted from the light emitting layer 9.

[0051] A current blocking layer 23 is provided between the p electrode 21
and the p-type clad layer 7. As shown in FIG. 4A, the thick part 13b has
portions not overlapping the current blocking layer 23, in a planar view
parallel to the light emitting face 20a. Accordingly, a straight current
path from the thin part 13c toward the p electrode 21 is blocked to
concentrate a drive current on portions of the light emitting layer 9
under the thick part 13b.

[0052] Further, a current blocking layer can also be provided under the n
electrode 29 to suppress light emission from the light emitting layer 9
under the n electrode 29, in order to improve the light emission
efficiency.

[0053] Next, a procedure for manufacturing the semiconductor light
emitting device 200 will be described with reference to FIGS. 5A to 7B.
FIGS. 5A to 7B show schematically a cross section of a wafer in each
process.

[0054] First, as shown in FIG. 5A, the n-type clad layer 5, the light
emitting layer 9, the p-type clad layer 7 are grown in sequence to form
the stacked body 20 on the sapphire substrate 31. These layers can be
formed using a metal organic chemical vapor deposition (MOCVD) method,
for example. Detailed configurations of the layers are the same as in the
semiconductor light emitting device 100 shown in FIG. 3.

[0055] Next, as shown in FIG. 5B, the current blocking layer 23 and the p
electrode 21a are formed on the second major surface 20b of the stacked
body 20. The current blocking layer 23 may use a silicon oxide film
(SiO2 film) formed by a chemical vapor deposition (CVD) method, for
example. The p electrode 21a may use a multilayer film in which nickel
(Ni), Ag, platinum (Pt), and Au are stacked in sequence from the p-type
clad layer 7 side, for example.

[0056] Next, as shown in FIG. 6A, a wafer 30 with the stacked body 20 and
the p electrode 21a, and a wafer 40 with the p electrode 21b formed on a
surface of the support substrate 25, are bonded to each other. The
support substrate 25 may be a p-type silicon substrate or a p-type
germanium substrate, for example. The p electrode 21b contains Au, for
example. In addition, as shown in FIG. 6A, a surface of the p electrode
21a and a surface of the p electrode 21b are brought into contact, and
the two wafers are subjected to weight bearing from a back side, and
thereby the p electrode 21a and the p electrode 21b are bonded to form
the p electrode 21.

[0057] Then, a YAG laser, for example, is irradiated to the wafer 30 from
the back side to dissociate partial crystal from the n-type clad layer 5,
thereby to separate the sapphire substrate 31 from the n-type clad layer
5, as shown in FIG. 6B.

[0058] Next, as shown in FIG. 7A, the transparent electrode 13 is formed
on the first major surface 20a of the stacked body 20 exposed by
separating the sapphire substrate 31. The transparent electrode 13 uses
an ITO film formed on the surface of the first major surface 20a by a
sputtering method, for example. A thickness of the ITO film is about 400
nm, for example.

[0059] Subsequently, a surface of the ITO film is selectively etched to
form the thick parts 13a and 13b and the thin part 13c. A thickness of
the thick parts 13a and 13b is 400 nm that is same as the thickness of
the ITO film, for example. A thickness of the thin part 13c is 200 nm,
for example. Further, the n electrode 29 is formed on a surface of the
thick part 13a (see FIG. 4A). The n electrode may use a multilayer film
in which Ni and Au are stacked from the transparent electrode 13 side,
for example.

[0060] Next, the stacked body 20 is selectively etched to define the light
emitting face 20a. Then, a bonding electrode 33 is formed on the back
face of the support substrate 25. The wafers are diced into individual
chips, thereby completing the semiconductor light emitting device 200.

[0061] FIGS. 8A and 8B are schematic views of chip faces of semiconductor
light emitting devices 300 and 400 according to modification examples of
the second embodiment.

[0062] For example, in the semiconductor light emitting device 300 shown
in FIG. 8A, a first thick part 13a is provided in a center of the chip
face, and a second thick part 13b is extended toward an outer edge of the
light emitting face 20a.

[0063] The semiconductor light emitting device 300 includes a rectangular
stacked body 20 with a long side and a short side, in a planar view
parallel to the light emitting face 20a as a first major surface. In
addition, the first thick part 13a is provided in a region including a
center of the rectangle. The second thick part 13b extends from the thick
part 13a in a long side direction and in a short side direction of the
rectangle. Accordingly, the light emitting face 20a with the n electrode
29 excluded can emit light evenly.

[0064] Alternatively, as in the semiconductor light emitting device 400
shown in FIG. 8B, the first thick part 13a may extend from the center of
the light emitting face 20a along the long side, and the second thick
part 13b may extend from the first thick part 13a toward the outer edge
of the light emitting face 20a.

[0065] That is, as shown in FIG. 8B, the semiconductor light emitting
device 400 also includes a rectangular stacked body 20 with a long side
and a short side, in a planar view parallel to the light emitting face
20a. In addition, the first thick part 13a has a region including a
center of the rectangle and portions extending from the region including
the center in the long side direction of the rectangle. The second thick
part 13b has portions extending in the short side direction of the
rectangle from the region including the center of the rectangle of the
thick part 13a, and portions extending from the portions extending in the
long side direction of the rectangle in the thick part 13a, in the short
side direction of the rectangle.

[0066] In this case, too, a minimum width W1 of the thick part 13a is made
larger than a width W2 orthogonal to an extending direction of the thick
part 13b. Accordingly, the light emitting layer 9 under the plurality of
thick parts 13b can emit light evenly.

[0067] The thick parts 13a and 13b shown in FIGS. 8A and 8B and similar
shapes can also be provided in the semiconductor light emitting device
100 according to the first embodiment.

[0068] In the second embodiment, the first conductivity type is n type and
the second conductivity type is p type. Meanwhile, in the first
embodiment described above, the first conductivity type is p type and the
second conductivity type is n type. However, the conductivity types are
not limited to the foregoing embodiments, but reversed conductivity types
may be used for each of the embodiments.

[0069] While certain embodiments have been described, these embodiments
have been presented by way of example only, and are not intended to limit
the scope of the inventions. Indeed, the novel embodiments described
herein may be embodied in a variety of other forms; furthermore, various
omissions, substitutions and changes in the form of the embodiments
described herein may be made without departing from the spirit of the
inventions. The accompanying claims and their equivalents are intended to
cover such forms or modifications as would fall within the scope and
spirit of the invention.

[0070] The "nitride semiconductor" referred to herein includes group III-V
compound semiconductors of BxInyAl.sub.zGa1-x-y-zN
(0≦x≦1, 0≦y≦1, 0≦z≦1,
0≦x+y+z≦1), and also includes mixed crystals containing a
group V element besides N (nitrogen), such as phosphorus (P) and arsenic
(As). Furthermore, the "nitride semiconductor" also includes those
further containing various elements added to control various material
properties such as conductivity type, and those further containing
various unintended elements.